In a technical field of such an occupant protection device, a signal line or a communication bus is usually arranged separately from an ignition voltage line. The signal line or the communication bus is used by an electronic control unit (ECU) to receive a signal from a sensor detecting a collision. The ignition voltage line is connected to a squib which ignites an inflator of an airbag and inflates the airbag.
In the JP-A-2006-015807 corresponding to US/20060000948A, for example, although a circuit configuration for an ECU to ignite a squib is disclosed, a description about a sensor system is omitted. Therefore, it is inferable that a signal line by which the ECU receives a signal from a sensor is separately located or that a collision detection sensor or the like is included in the ECU.
The inventor of the present disclosure has found the following. In the occupant protection device such as the airbag, since a signal line and an ignition voltage line are arranged separately, the configuration requires more man hours and results in a heavier and larger device due to the line.